From a reader:

Jonah, enjoyed your conversation with Peter Beinart, I just want to point out one thing. When he talks about income stagnating, it’s just not true. If you adjust it for inflation, the average income of the middle class has risen tremendously: http://www.infoplease.com/ipa/A0104583.html It hasn’t risen as much for the poor, but that still has risen and while I don’t have the numbers for single income earners in front of me, those have risen a lot as well (it isn’t just a case of an increase from both parents working). Beinart can argue about working more hours, but given how great a difference there is between the total numbers three decades ago and today, it’s really a stretch to say people are worse off just based on economic stats (forgetting for a second the advances in medicine, technology, etc.). Obviously some goods and acquiring housing are more expensive today, but as you mentioned, if you look at the quality of much of it in the 1970s, that is also a far cry from what it is today as well. To add to that, this happened during a time when we’ve taken in millions of people who grew up in poverty in other countries (a fact that would increase low income earners without necessarily indicated a “poor getting poorer scenario”).

Update: From a reader:

Your earlier correspondent was incorrect. Or at least, his data was. The numbers given as the median at his link are actually the mean.
The real median household income has still not recovered to where it was in 1999. This is shown here in the data from the Census Bureau..
http://www.census.gov/hhes/www/income/histinc/h05.html
What is more, household income disguises the fact that wages are pretty stagnant. The median income for *individuals* has scarcely changed in the last thirty years. *Household* income has climbed as more and more households have more than one wage earner.
Lastly, to the point about inequality, the rising gap between median and mean income the above data demonstrates the rising inequality.